An exemplary silicon carbide semiconductor device includes a silicon carbide substrate and a main electrode in ohmic contact with the silicon carbide substrate. For example, in the case of a MOSFET (Metal Oxide Semiconductor Field Effect Transistor), an ohmic electrode on a silicon carbide substrate is required as a source electrode serving as one of main electrodes. As an ohmic electrode having a low contact resistance, an ohmic electrode containing aluminum (Al) has been known. Moreover, on the ohmic electrode, an interconnection layer is usually provided. Such an interconnection layer is often made of a material such as Al or an alloy thereof. For example, WO 2009/128382 (Patent Document 1) discloses a MOSFET including: a source electrode containing Ti, Al, and Si; and an interconnection layer provided thereon and made of Al.